It is known to make bags from a synthetic-resin tube in accordance with the procedure such as described in my copending application Ser. No. 127,064 filed Mar. 4, 1980 (now U.S. Pat. No. 4,333,298 issued June 8, 1982). The tube is delivered to a cutting/welding station where simultaneously it is engaged by an upstream welding bar that forms a transverse weld across the tube, and by, immediately downstream of the seam, a blade which transversely cuts the tube through, creating a bag blank whose downstream end has already been sealed in the previous cutting operation. This blank is then transported downstream, normally either by a conveyor or a drum, to a stamping station where the open upstream end is punched out to form handles. It is also known to stack the bag blanks immediately downstream of the cutting/welding station and to transport this stack downstream for simultaneously punching out the handles of all of the bags in the stack.
Such a procedure works relatively well so long as relatively thick film is used. With thick film the bag blanks are relatively easy to handle and can be counted on to lie flat on top of one another. When thinner film is used, however, it is normally necessary to greatly decrease production speed due to the considerable difficulty of handling the thin film. What is more, it is almost impossible to neatly stack bags formed of extremely thin film, since air is normally captured in and between the bags so that a puffy and hard-to-handle stack is produced.
It has been suggested to block the stack of bags together, normally by forming a small weld through the entire stack. This can simply be done by passing a heated needle through the portion of the stack that is later cut away at the punching station. This heated needle forms a weld that secures together all of the bags of the stack.
This type of blocking is relatively effective, once again, for thick film. Nonetheless when thin film is used it is still quite difficult to transport a stack of bag blanks, even when same have been blocked together in the above-described manner.